In the present study we report the micellization behavior of imipramine hydrochloride (IMP) in absence and presence of different concentrations of inorganic salts (LiCl,NaF,NaCl,NaBr,and KCl) and ureas (urea and thiourea) over the temperature range from 288.15 to 303.15 K.The critical micellization concentrations (cmc) of drug and drug + additive systems were determined by conductometric technique.With increasing temperature the cmc first increases then decreases.Maximum cmc values were obtained at 293.15 K with or without additives.In presence of inorganic salts the cmc value decreases which is explained on the basis of nature and ion size of the added ion.Urea and thiourea also decrease the cmc at low concentrations (0.2 mmol·L-1 urea and 0.1 mmol·L-1 thiourea),but,at higher concentrations,increase in cmc is observed.The related thermodynamic parameters are also evaluated and discussed.